Spark-plug.



(l me/MM Patented Oct. 12, 1915.

J. w. MEAKER. SPARK PLUG.

APPLICATION FILED JAN-2.1913.

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JOHN W. MEAKER, 0F DETROIT, MICHIGAN.

SPARK-PLUG.

Specification of Letters Patent.

Application filed January 2, 1913. Seria1.No. 739,908.

To all whom it may concern:

lie it known that I, Jon) \V. MnAKnR, a citizen of the United States of America, residing at Detroit, in the county of \Vayne and State of Michigan, have invented cer tain new and useful Improvements in Sparkllugs, of which the following is a speciiication, reference being had therein to the accompanying drawings. In a construction of spark plugs for explosive engines that are subjected to rough usage, as on automobiles or the like, it is' desirable that the body of the plug, ordinarily of porcelain or other frangible vitreous material, be'as large as possible to lessen the liability of breakage. It is also desirable, inasmuclras the plugs are made in large quantities, that the mechanical construction be simplified to reduce the cost of manufacture without impairing the efficiency.

This invention relates to spark plugs and to an arrangement thereof whereby the body of the plug is not liable to fracture and whereby the parts are readily machined and assembled. The invention also includes a disposition of the ignition terminals or spark points which minimizes the accumulation of sootand dirt thereon.

The invention consists in the matters hereinafter set forth and pointed out in the appended claims.

In the drawings, Figure 1 is a view, partially in elevation and partially in longitudi nal section. of one type of spark plug that embodies features of the invention; Fig. 2 is a. bottom plan view of the plug; Fig. 3 is a view showing a modification of the lower part or nipple of the plug; Fig. 4 is a view showing a further modification; Fig. -5 is a view in detail showing a spark plug with one part omitted; and Figs. (3, 7 and S are views in detail showing one form of spark terminals.

As herein. shown. an outer casing 1 is interiorly scrcw-tln-eaded to receive a stop collar 2 that is thereby adjustably positioned longitudinally in the casing. A body of porcelain or refractory insulating material has an enlarged central portion 3 and tapered depending portion 4, the body being secured in position by an annular bushing 5 forcing the portion 3 to seat against the stop collar Suitable packing rings 6 are interposed to atTord a tight joint. The upper portion 7 ot the body is as large as the bushsuitable head 15 on the ing 5 will permit and is provided with the usual cap 8. The casing 1 is secured in position by a screwthreaded nipple 9 that is turned to seat against the under side of the stop collar The lower portion of the nipplc is slotted or convenient application of a turning tool or wrench and is provided with sparking terminals to coact with a stem 10 in the body. These terminals as shown in Fig. 1, comprise a pair of parallel loops 11 with inclined body portions so that lubricant lodging thereon 'runsto the lower bend or corner and drops oii without interfering with the spark gaps. Or, as indicated in Figs. 6, 7 and 8, the terminals may take the form of a. corrugated wire 12 secured on an end flange 13 ot' the nipple by pcening over a shoulder shown at l-l. and arranged to coact with a body stem. Preferably the head is formed of a sheet metal blank drawn and slotted as shown that is fixed to the stem head. The shape of the corrugated wire prevents the lodging of soot thereon and by bending the loops downwardly, adjustment is afforded to get the de sired interval between the center terminal and loops. The loops may be formed, however, separable or otherwise, and may be secured in any suitable manner. I

The collar 2 shown in Fig. 1 maybe replaced by a ring .17 as indicated in Fig. l with an additional packing ring 18, against which the nipple bears. Or the collar may be entirely omitted as nidicated in Fig. 5, in prov ded to which instance a nipple 19 is bear upwardly against a suitable. packing ring 20 and a lower shoulder of the central portion 3 of the body.

in either form of construction space is atlorded for a body having a large cross sectional area which reduces liability of fracture while the parts that support the body are readily assembled and are machined with a minimum number of stepsv The exterior or projecting portion of the nipple may have the same diameter and thread as the portion inserted in the body, or it may have a dificrent provided with serewthreads of any pitch. This enables the plug as av whole to be readily adapted for use with any make of motor, as the nipple is easily designed to meet a. special requirement without altering the body or casing of the nipple.

Obviously changes in the details of 0011-.

diameter and be.

Patented Oct. 12, 1915.

otherwise arranged for the care to limit myself to any particular form or arrangement of parts.

What I claim is 1. A spark plug comprising an interiorly screwthreaded casing, an exteriorly screwthreaded nipple in engagement with said casing and protruding from the lower end thereof and adapted to belimited in its movement relatively to said casing and provided with a spark terminal near the outer end, a body of insulating material having an intermediate enlarged portion in the casing and carrying a terminal stem co-acting with the nipple terminal a packing member between the inner end of the nipple and the enlarged portion of the body, and a bushing in screwthreaded engagement with the easing encircling the body and forcing the latter against the packing ring and toward the nipple end. i

2. A spark plug comprising an interiorly screwthreaded casing, an exteriorly screwthreaded nipple in engagement with said casing protruding from the lower end there of and having a spark terminal near the outer end, means within the casing forming a shoulder for limiting the movement of the nipple relatively to the casing, a body of insulating material having an intermediate enlarged portion in the casing and carrying a terminal stem co-acting with the nipple terminal, packing between the inner end of the nipple and the-enlarged portion of the body, and a bushing engaging the casing and. encircling the body for forcing the latter against the packing ring toward the nipple end.

In testimony whereof I aIliX my signature in presence of two witnesses.

JOHN W. MEAKER.

Witnesses C. R. S'rlonnny, A. M. Dorm. 

